Electric heating furnace



Aug. 22, 1933.

G. L. slMPsoN 1,923,644

ELECTRIC HEATING FURNACE 3 Sheets-Sheet l Filed Jan. l1, 1932 e Zw ze Y j 3mm/m Aug.I 22, 1933. L S|MPSQN 1,923,644

ELECTRI C HEATING FURNACE Filed Jan. ll, 1932 3 Sheets-Sheet 2 Aug. 22, 1933. G. l.. slMPsoN 1,923,644

ELECTRIC HEATING FURNACE Filed Jan. 1l, 1932 5 Sheets-Sheet 3 Patented Aug. 22, 1933 UNITED STATES ELECTRIC HEATING FURNACE George L. Simpson, Coraopolis, Pa., assignor to Pittsburgh Research Pa.

Application January v 11,

35 Claims.

My invention relates to electric heating furnaces and more particularly to a means and method for supporting resistance heating elements therein.

An important object of my `invention is to provide a support for resistance elements, such as those shown anddescribed in my co-pending application No. 580,689 for Electric heating furnaces filed December 12, 1981, which consist of plates which'may be unbroken or slit and which, for the best results, should be supported in spaced relation to the walls of the furnace.

Another object of my invention is the provision of a resistor support which. will permit free eX- pansion and contraction of the resistor'element.

A further object of my invention is to supporta resistance heating element in spaced relation to the walls of the furnace to permit the utilization of the heat of that side of the resistor which faces away from the charge.

Yet another object of my invention is the provision of a resistance heating element which may be readily removed and replaced.

Other objects and advantages of my invention 25, will be apparent during the course of the following description.

In the accompanying drawings, which form a part of this specification, and wherein like. characters of reference denote like or corresponding parts throughout the same,

Figure 1 is a fragmentary sectional view of a furnace showing my improved resistance element mounted therein,

Figure 2 is `an elevation of a portion of the resistor and the supporting blocks therefor,

Figure 3 is ardetail sectional view on the line 33 of Figure 2,

Figure 4 is a fragmentary sectional view of a portion cf a furnace having a modified form ofresistor and resistor support,V

Figure 5 is a similar View of a further modification of my invention, r

Figure 6 is a similar view of still'another form of my invention,

Figure 7 is a similar view of of my invention,

Figure 8 is a detail section on the line 8 8 of Figure '7,

Figure 9 is a fragmentary sectional view of a furnace embodying yet another form ofmy invention, Y

Figure 10 is a similar view of another modification of my invention,

Figure 1l is an elevation of a portion of the resistor shown in Figure 10,

a still further form into contact with the wall 15.

Corporation, Pittsburgh,

1932. serial No. 585,994

Figure 12 is a sectional view of a portion of the resistor element and illustrating one method of inserting the resistor into the supports, and,

Figure 13 is a perspective view illustrating the method of inserting the resistorinto the supports.` j

In the drawings, wherein for the purpose of illustration is shown al preferred embodiment of my invention the numeral 15 designates a portion of the wall of a heating furnace, such for example as shown in my co-pending application referred to above. The resistance element/16 may be an unbroken plate or it may be provided with suitable slits, as shown in Figure 2, although other forms of resistance elements may obviously be used.V A horizontal row of supporting blocks 17 of refractory material are embedded in the wall l5 adjacent the top thereof and project a substantial distance inwardly from the Wall, as seen in Figure 1. Each of the blocks is provided adjacent its projecting end with a transverse cylindrical bore 18 which communicates with the lower face of the block by means of a transverse slot 19 the width of which-is substantially less than the diameter of the bore 18. The resistor plate` is adapted to extend `through the slot 1.9.into the bore 18 and is provided adjacent its upper end with pins or projections 20 which extend through the plate 16 and project from bothv sides thereof. The projections 20 are too -large to `be pulled 85 through the slot 19 and therefore rest upon the lower walls of the bore 18 and support the plate 16 in spaced relation to thewall 15. In order to prevent contact of the flower, end of the plate 16 with the wall 15 or with the charge 90 I 'provide a second row of blocks 17 having grooves to receive the lower end of the plate. The blocks 17 may, for convenience of manufacture, correspond exactly with the blocks 17, but are arranged in an inverted position. The groove receives theplate 16 which does not extend to the bottom thereof, to allow for expansion, and the plate is prevented from Swingin In place of the groove 18 any other form of 100 groove may be employed, such as a plain groove. In place of the cylindrical bore 18, any other form of bore may be` used, such as a rectangular bore. It is necessary however to have a ledge or shoulder upon which theV pins 20 may rest, and thisl 10,5 shoulder is provided by the difference in width between the slot 19and bore 18. l

Instead of `having a continuous row of blocks 17 and 1'7, the blocks may be spaced apart. Where the plate is slit however, asin Figure 2, each section of the plate should engage a block to prevent twisting and warping of the resistor.

The blocks 17 and 17 may be provided with vertical openings between the bore 18 and wall 15 to permit a circulation of the furnace atmosphere and the utilization of the heat of the side of the plate 16 which faces the wall `15.

The plate 16 is supported at its upper end and does not extend to the bottom of the groove 18' norto the top of the bore 18. Consequently freedom of expansion is provided, and this expansion of the plate will not interfere with the support thereof.

In Figure 4 the upper and lower blocks 22 are secured to the wall 15 by means of bolts or other securing means 23, instead of being embedded in the wall. AIn carrying out my invention, either form of securing means may be employed, howu ever. The blocks 22 are otherwise similar to the blocks 17 and 17. It is sometimes desirable to support the resistor plates at their lower ends, as well as their upper ends, for example, when l the plates are so high or so heavy that they would otherwise tend to sag under their own weight. In Figure 4 the resistor plate 24 is supported at its upper end in the same manner. as

in Figure 1 but the lower end of the plate is arranged immediately adjacent the bottom of the block groove or may rest thereon. The plate will therefore be supported at top and bottom. In order toV allow for expansion of the plate, I provide corrugations 25 which extend longitudinally of the plate, preferably adjacent the bottom thereof.

In place of the corrugations 25, however, I may v utilize the space between the top of the plate 24 and the top of the groove in the upper block te take care of expansion of the plate. With such an arrangement, the pins 20 may be dispensed with, if desired, as the plate will be supported at its lower end. If the pin 20 is omitted, however, the plate will have to be of a construction such as will permit its standing on end without deformationunder its own weight. v

In Figure 5` the supporting blocks 26l are provided with plain grooves 27 into which the heating plate 28projects. l Pins 29 extendgthrough the outer portion ofthe upper blocks and through the grooves 27 transversely thereof. 'Ihe pins 29 extend through suitable openings in the top of the plate and -serve to support the plate with its lower end spaced from the bottom of the groove in the'lower blocks.Y If desired, the plate may rest on then bottom of the lower groove andbe provided with corrugations as in Figure 4. If

the strength of the plate permits, the corrugations and'pins may be dispensed with, and the plate supported in the Vlower groove with its upperV end spaced from the top of the upper groove.

In the form of my invention shown in Figure 6,

the supportingblocks 30 are provided with'sub-Y stantially inverted L-shaped grooves 31. The plate A32 is bent over at its upper end to form a righ-t angle flange 33 which rests upon the shout1 der" of the h-shaped. groove and supports the plate The lower end of the plate extends into the groove in the lower blocks 30 and may be spaced from thebottom of the groove as inFigure 5.l The plate is shown, however, as resting f the flange 33 and the top of the groove 31 may be used to permit expansion of the plate.

In the form of my invention illustrated in Figure 7, the blocks 34 are provided with T-shaped grooves 35, the plate 36 having its upper end provided with a plurality of slits forming tabs 37 which are vbent alternately in opposite directions to rest upon the shoulders of the groove 35, as seeny in Figures 7 and 8. The plate 36` may be spaced from the bottom of the lower groove as shown in Figure 5, but it is shown as resting upon the bottom of the groove and has expansion taken up by corrugations 25 although this result may also be obtained by utilizing the space between the tabs 37 and the top of the upper groove.

In Figure 9 the plate 38 has openings adjacent its top which receive bolts 39 supported by refractory blocks 40 which are embedded in the walls of the furnace. A spacingelement 41, of refractory material is arranged between the wall of thejfurnace and the plate 38 and is supported by the bolts 39. The lower end of the resistance plate extends into a groove 42 in lower blocks 43 which may be embedded in the furnace wall as shown, or which may be bolted to the furnace wall as in Figure 4. The bottom of the plate may be spaced from the bottomof the groove as shown in full lines, or may rest thereon and be provided with corrugations such as shown at 25 in Figure 4.

In Figure 10 the bolts 39, blocks 40 and spacer 41 are duplicated at the lower end of the plate and the plate is supported at top and bottom. The openings 44 in the plate 45, shown in Figure 11 receive the upper bolts 39 and elongated slots 48 in the plate receive the lower bolts 39 and permit freedom of expansion.y The position of the openings 44 andiflf may be reversed, or openings such as 44 may be substituted for slots 46 and corrugations provided to permit expansion of the the resistor plates may be slid into place in the supporting blocks from the end of the row of blocks while building up the furnace walls. In some other types of furnaces, such as hood type furnaces, this method of inserting the plates may be impracticable and it is necessary to insert the plates at some point spaced from the endsof the block rows. This may be accomplished by leaving out one of the blocks or a portion thereof and flexing the plate to insert it into the grooves of the block through the open space left bythe omitted block. Another method is that shown in Figures 12 and 13 in which a special block 47 is arranged in each of the rows 17 and 17. The blocks 47 are similar to the blocks 17 and 17 but have their inner ends cutaway at 48 to the depth of the grooves 18 and 18 for a portion of their length, the remainder of the length of the blocks being curved to the grooves as at 49. 'Ihe plate can then be inserted into the grooves through the cutaway portions 48 and guided by the curved portions 49 by flexing the plate as shown in Figures 12 and 13,.

Other means than that shown may be utilized :for inserting the plates into the grooved blocks, andthe arrangement shown in Figures 12 and 13 is applicable to other types of plates and supporting'blocks than those illustrated. It will alsonbe seen that the various forms of my `invention may y be applied to other forms ofplates'than that illustrated, such as an unbroken. plate, or a plate having a different arrangement of slots than that shown. The portion of the furnace `wall indicatedv at 15v is a diagrammatic representation of the wall of any suitable type of furnace, as for example, a box type furnace or a hood typeheating furnace.

The supporting blocks in all forms of my invention may be embedded in 'the wall as in Figure 1, or bolted to the wall as in Figure 4, or securedl in any other suitable manner.

In mounting the plate, its lower end is spaced from the bottom of the lower groove a distance which will permit maximum expansion of the plate without its contacting with the bottom of the groove. In all formsof my invention, however, the arrangement shown in Figure 4 in which this space is omitted and expansion taken up by the corrugations may be used, or the top of the plate may be spaced a sumcient distance from the top of the upper groove to allow for maximum expansion of the plate.

The openings 2l may be used wherever it is desired to utilize the heat of the side of the plate facing away from the charge, or the same result may be obtained by spacing the blocks from each other. Not only do the blocks serve to support the plate, but where the plate is slit, as seen in Figure 13, the free ends thereof are confined by Cfr While I have shown and described the preferred embodiment of my invention, it is to be understood that various changes in the size, shape and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. In an electric furnace, a resistor plate, means extending inwardly from the wall of the furnace to support said plate in spaced substantially parallel relation to said wall and to maintain the plate out of contact with the furnace wall and charge, said plate being free to expand and contract, and means whereby the heat from the side of the plate facing the furnace wall may be utilized to heat the furnace charge.

2. In an electric furnace, a resistor plate, a support extending inwardly from the wall of the furnace, said support having means to engage and to support'the upper end of said plate in spaced relation to the wall of the furnace, and means carried by said furnace wall to prevent movement of the lower end of the plate toward and away from said Wall.

3. In an electric furnace, a resistor plate, a pair of supports carried by the wall of said furnace and spaced apart vertically, said supports having means to hold the resistor plate in spaced relation to the furnace wall and to confine the upper and lower ends of the plate while permitting expansion and contraction of the plate.

4. In an electric furnace, a resistor plate, a support arranged in said furnace, said support having a groove therein adapted to receive the plate, said groove having a shoulder, and means on said resistor plate to engage the shoulder of the groove and support the plate.

5. In an electric furnace, a resistor plate, a pair of vertically spaced supports extending inwardly from the wall of the furnace, said supports having grooves on adjacent faces, said grooves being spaced from the furnace wall and adapted to receive the resistor plate to support the plate while permitting expansion and contraction thereof.

6. Inv an electric furnace, a resistor plate, a refractory support extending inwardly from the furnace wall, said support having a groove in the under side thereof, said groove being enlarged adjacent its upper end, the groove being adapted to receive the upper end of the resistor plate, and a projection on said plate adapted to be arranged in the enlarged portion ofthe groove to suspend the plate from the support.

'7. In an electric furnace, a resistor plate, a refractory-support extending inwardly from the furnace wall, said support having a groove in the under side thereof extending along the wall of the furnace, said groove being enlarged adjacent its upper end, the groove being adapted to receive the upper end of the resistor plate, a projection on said-plate adapted to be arranged in the enlarged portion of the groove to suspend the plate from the support, and means to restrict the movement of the lower end of the plate.

w 8. In an electric furnace, a resistor plate, a refractory support extending inwardly from the furnace wall, said support having a groove in the under side thereof, said groove being enlarged adjacent its upper end, the groove being adapted to receive the upper end of the resistor plate, a projection on said plate adapted to be arranged 'in the enlarged portion of the groove to suspend larged portion of the groove to suspend the plate from the support, and means to support the lower end of the plate, said plate being free to expand and contract.

10. In an electric furnace, a resistor plate, a pair of vertically spaced supports `extending inwardly from the wall of the'furnace, said supports having grooves on adjacentk faces, the

grooves being adapted to receive theA resistor plate 1 on said plate adapted to be arranged in the eni to support the plate, said plate being provided pair of supports carried by the wall of the furnace and extending inwardly therefrom, said supports being adapted to support the resistorplate in spaced relation with the vfurnace wall, and said plate being provided with longitudinally extending corrugationsto allow expansion and contraction of the plate.

l2. In an electric furnace, a pair of supports carried by the wall of the furnace and extending inwardly therefrom, said supports having grooves to receive the resistor plate, and means on one of said supports to engage a portion of the resistor plate adjacent its upper end to support the plate in spaced relation to the furnace Wall. i

'i 13. In an electric furnace, a resistor plate, a

pair of supports carried by the wall of the furnace and extending inwardly therefrom, said supports having grooves to receive the resistor plate, and means on one of said supports to engage a portion of the resistor plate adjacenty its upper end to support the plate in spaced relation to the furresistor plate, a

nace Vwall while allowing free expansion and `con-v I and extending inwardly therefrom, said supports having grooves to receive the resistor plate, and a pin extending through the resistor-plate andengaging one of the supports.

15,:Inran Velectric furnace, a resistor plate, a pair of supports carried bythe wall' of theful.- nace and extending inwardly therefrom, said supports having grooves to receivethe resistor plate, and a pin extending through the resistor plate and engaging one of the supports to support the plate, said platehaving corrugations to permit free expansion and contraction thereof.

16..In an electric furnace, a resistor plate., a support carried bythe wall of said furnace and extending inwardly therefrom, said support having a substantially inverted L-.shaped groove in Ythe under side thereof, said resistor plate being bent over at ,its upper end to form a flange adapted Yto be 'received in the groove of the support, and means to restrict movement of the lower` end. of the plate while permitting expansion and contraction vertically of the plate.

18. In an electric furnace, a resistor plate, a support carried by the wall of said furnace and extending inwardly therefrom, said support having asubstantially inverted L-shapedgroove in the under side thereof, said resistor plate being bent over at its upper end to form a flange adapted to be received-in the groove of the support, and. ineans to support the lower end of the resistorl plate, said plate `having corrugations therein to permit expansion and contraction verticallyof the plate.

19. In an electric furnacea resistor plate, a support carried by the wall of the furnace, said support having a substantially T-shaped groove .in the under side thereof, and said resistor plate having its upper end provided with tabs bent in opposite directionsand adapted to be received by the groove in the support.

20. In an electric furnace, a resistor plate, a support Ycarried by the Wall ofthe furnace, said support having a substantially T-shaped groove in the under side thereof, and said resistor plate having Yits upper end provided with tabs bent in opposite directions and adapted to be received by the groove the support, and means to restrict movement of the lower end of the plate while permitting expansion and contraction of the plate.

21. In anl electric furnace, a resistor plate, a support carried by the wall of the furnace, said support having a substantially T-shaped groove inthe under side thereof, and said resistor plate havingits upper end provided `withtabs bent in opposite directions and adapted to be received by the groove in the support, and means to supl portthe lower end of the resistor'plate, said plate having corrugations therein to permit expansion and contraction of the plate.

22. In an electric furnace, a resistor plate, a

Vsupport carried by the Wall of said furnace and extending inwardly therefrom, said support having asubstantially inverted L-shaped groove in the under side thereof, said resistor plate being bent over at its upper end to form a flange-adapted to'be received in the groove of the support, whereby said plate is supported in vspaced relationto the wall of thenfurnace, and means whereby the atmosphere of the furnace may circulate between the plate and furnace wall and vertically past the support.

23. In an electric furnace, a resistor plate, a support carried by the wall of the furnace, said support having a substantially T-shapedgroove in the under side-thereof, and said resistor plate having its upper end provided with tabs bent yin opposite directions and adapted to be received by the groove in the support, whereby said plate is supported in spaced relation to the wall-of the furnace, and means whereby the atmosphere of the furnace may circulate between the plate and furnace wall and vertically past the support.

24. In an electric furnace, a resistor plate, resistor supports carried by the wall of the furnace.

and extending through the resistor plate, said plate being free 'to expand and contract.

25.. In an electric furnace, a resistor plate, a resistor support carried by the furnace wall and extending through :the plate adjacent the upper. end thereof, means to space the resistor plate from the furnace wall, and means to restrict movement of the lower end of the plate.

26. In an electric furnace, a resistor plate, a resistor support carried by the furnace wall and extending through the plate 'adjacent thefupper` end thereof, means to space the resistor plate from the furnace wall, and means `to restrict movement of the lower end of the plate while permitting expansion and contraction of the plate.

27. 'In an electricA furnace, .a resistor plate,.resistor supports carried. by the wall of the furnace` and extending through the` resistor plate, said supports permitting expansion and contraction of the resistorplate, and means to space the plate from the.- furnace Wall.

128. In an electric furnace, a resistance plate having slits therein dividing the plate into a plurality .of connected sections, and means to support the plate in spaced relation to the furnace wall, said supporting means being carried by.

the furnace wall and serving to confine the sections of the resistor plate to prevent distortion thereof.

29. In an electric furnace, a resistor plate, a

row of supporting members carried by the furnace wall and provided with bores extending therethrough, said bores communicating with the lower faces of the supporting members by means of restricted grooves, said plate having projections therein adapted to be received by the bores in the supporting members and being of a formtoy sert the plate into the grooves of the supportingy members at a point spaced from the ends of the supporting members. 1

3l. In an electric furnace, a resistor plate having slitstherein to form a circuitous pathforthe electric current, a pair of supports carried `by the wall vof theV furnace and spaced apart, `said.

supports having meansto Ahold the resistor `plate in spaced relation to thefurnace wall andzto.

confine the upper and lower ends of the plate while permitting expansion and contraction of the plate.

32. In an electric furnace, a resistor plate, a pair of supports arranged in said furnace and spaced apart vertically, said supports having means to hold the resistor plate in spaced relation to the furnace wall and to conne the upper and lower ends'of the plate while permitting eX- pansion and contraction of the plate.

33. In an electric furnace, a heating element comprising a relatively thin metallic resistor plate supported in spaced relation to the furnace wall and out of contact with the furnace wall and charge.

34. In an electric furnace, a heating element GEORGE L. SIMPSON. 

